Purification of coke-oven gases and the like



UNITED STATES 1,717,76 PATENT OFFICE.

GEORGES CLAUDE, OF PARIS, FRANCE, ASSIGNOR TO SOCIETE LAIB; LIQUIDE, SOCIETE ANONYME POUR LETUDE ET IIEXPLOITATION DES PROCEDES GEORGES CLAUDE,

OF PARIS, FRANCE, A CORPORATION OF FRANCE.

PURIFICATION OF COKE-OVEN GASES AND .THE LIKE,

No Drawing. Application filed November 4, 1926, Serial No. 146,280, and in France -November 17, 1928'.

The preliminary purification of coke oven gases and the like, the constituents of which are to be separated by means of 1i uefaction is, as is well known, of considerab e importance. The present invention relates to the purification of such gases which are to be ultimately subjected to such li uefaction treatment, and has particular re erence to improvements in carrying out the latter stages ofthe purification treatment so asvto remove from the gases substances which were ordinarily retained therein with the processes as heretofore carried outand also to effect a thorough drying of the gases and the removal therefrom of any residual amounts of reagents employed in the course of the treatment of the gases.

, After the separation of the tar, the crude coke ovengases are subjected to treatment for the removal, firstl of liquid and solid particles, secondly of hydrocarbons such as enzene, toluene, etc., and thirdly of carbon dioxid and sulphuretted hydrogen by any known methods as desired, among which the the gases by treatment with cresol or any other specially eflicacious solvent in a second Raschig ring tower. This cresol, after having been heated so as to eliminate the very small quantities of the hydrocarbons that it has absorbed, is afterwards returned into the circuit. The quantities of suchhydrocarbons absorbed by the cresol or other solvent will not in general be worth while recovering, but it is important to remove them from the gases as their presence might be very inconvenient since 1t might result in obstructin the liquefyin apparatus.

The car on dioxid an an sulphuretted hydrogen are then removed y passing the v gases through a column provided withRas--:

retted hydrogen therefrom, and thus render.

the absorbing ammoniacal solution available for re-use in the process, or it may be distilled and the ammonia evolved led to a suitable apparatus where the ammonia is converted into sulphate or other products.

The ammonia which remains in thegirses is removed in a tower (or in an extension of the preceding one wherein the carbon dioxid is removed) through which a current of water is circulated. In the second'case,

referred to in the preceding paragraphgi.

namely where the ammoniacal solution is distilled after use, this water can be utilized in the manufacture of the ammoniacal solu-; tion.

be as complete as possible, the treatment of the gases with ammonia for thispurpose is completed by treatment with a caustic alkali solution, .such as sodium or potassiu mehy droxid, in another column.

According to the present invention, the removal of carbon dioxid-from the gmesis rendered complete by" treating them with-a.- solution of caustic soda, potash or other caustic alkali or alkalies, inorganic o'r organic, alone or admixed, containing accrtai-n proportion of di-, tri-, or other polyhydrie alcohols, such, for example, asglycerme- (or-- dinar glycol) ethylene glycol, trimethylene glyco, etc., alone or in mixture'with each other, whereby atthe same time the absorp tion of carbon oxysulphid or other organic sulphur compounds that ma be resent is also efl'ected by the said solution. he gases, after subjectionto this treatment, may still: contain in addition to moisture traces of ammonia and soda or other alkali, of which they must be deprived with the greatest care; for this purpose they may be subjected in a final column of the apparatus to the action of a current of sulphuric acid, which thus furnishes the triple result of drying the gases and at the same time removing the traces of soda, etc., and ammonia.

As the absorption ofcarbon dioxid haste-= This method of dryi-n'gflfthe gases is espe-I acid which pass into the dehydratin when they are made of such materia Furthermore if, in accordance with a further feature of this invention, there be added to the sulphuric acid very small quantities of an appropriate catalyst, such as tungstic oxid, vanadic oxid, etc., this catalyst, under the influence of pressure, will permit the rapid absorptionv in the acid of a lar e part of the ethylene present, which may e converted into alcohol. The sulphuric acid carried alon by the gases may be retained by passin "t em through a supplementary receptac e, containin solid soda if need be.

The. present app ication is in part a sub: stitute for, and in part a continuation of, my prior application, Serial No. 7 44,822, filed October 20, 1924.

I claim as my invention 1. A process for the preliminary purification of gases intended to be subJectedto partial liquefaction for the separation of their various constituents, wherein after the gases have been freed from tar, liquid and solid particles and hydrocarbons, and the greater, part of the carbon dioxid has been removed, the removal of carbon dioxid and inorganic sulphur compounds from the gases is rendered complete by treating them with a solution of-caustic soda'containing a certain proportion of glycerine.

2. A process as claimed in claim 1, in which the gases, after treatment with the caustic soda solution containing glycerine, are treated with sulphuric acid so as to remove moisture and traces of soda and ammonia.

taining. glycerine.

4. In a process for the removal of organic sulphur compounds from a gaseous mixture containing them, the steps of treating the gases first with a solution of caustic soda containing glycerine, and thereafter with sulphuric acid to which a catalyst has been added.

- 5. In a process for the removal of organic sulphur compounds from a gaseous mixture containing them, the step of treating the gases with a caustic alkali solution contain-- ing a polyhydric alcohol.

6. In a process for the removal of organic sulphur compounds from a gaseous mixture containing them, the steps of treating the gases first with a caustic alkali solution containing a polyhydric alcohol, and thereafter with sulphuric acid to which a catalyst has been added.

7. A process for the preliminary purification of gases intended to be subjected to pai'tial liquefaction for the separation of their various constituents, whereln after the gases have been freed from tar, liquid and solid particles and hydrocarbons, and-the greater part of the carbon .dioxid has been removed, the remaining carbon dioxid and the organic sulphur compounds are removed from the gases by treating them with a caustic alkali solution containing a polyhydric alcohol.

8. A rocess according to claim 7, in which t e gases, after treatment with the caustic alkali solution containing a olyhydlric alcohol, are treated with sulphuric aci 9. The process of purifying a hydrogencontaining gaseous mixture contaminated with organic sulphur compounds, which comprises contacting said gaseous mixture with a solution of caustic alkali and glycerin.

10. The process of purifying a hydrogen-containlng gaseous mixture contaminated with organic sulphurcompounds, which comprises contacting said gaseous mixture with a solution of caustic alkali.

and a polyhydric alcohol.

In testimony whereof I aflix my signature.

' GEORGES CLAUDE. 

